From a9ee07914eaf2fdc04f955b35f01bb7df005e806 Mon Sep 17 00:00:00 2001
From: SY Wang <uwsy1059@qq.com>
Date: Sun, 16 Aug 2026 19:24:02 +0800
Subject: [PATCH] Parallel DFT-D4 with MPI through work-partition

---
 CMakeLists.txt                                |  9 ++++---
 .../module_vdw/test/CMakeLists.txt            | 10 ++++++--
 source/source_hamilt/module_vdw/vdwd4.cpp     | 25 +++++++++++++++++++
 toolchain/scripts/package_versions.sh         |  4 +--
 4 files changed, 41 insertions(+), 7 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 34505c5c24e..b64e168f726 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -311,7 +311,7 @@ endif()
 if(ENABLE_PEXSI)
   find_package(PEXSI REQUIRED CONFIG)
   if(PEXSI_VERSION VERSION_LESS "2.0.0")
-    message(FATAL_ERROR "PEXSI >= 2.0.0 is required")
+    message(FATAL_ERROR "PEXSI >= 2.0.0 is required; found version ${PEXSI_VERSION}")
   endif()
   set(CMAKE_CXX_STANDARD 14)
 endif()
@@ -369,7 +369,10 @@ if(NOT USE_KML AND NOT MKL_FOUND AND NOT USE_SW)
 endif()
 
 if(ENABLE_DFTD4)
-  find_package(dftd4 4.2.0 REQUIRED)
+  find_package(dftd4 REQUIRED)
+  if(dftd4_VERSION VERSION_LESS "4.3.0")
+    message(FATAL_ERROR "dftd4 >= 4.3.0 is required; found version ${dftd4_VERSION}")
+  endif()
 endif()
 
 include(CheckLanguage)
@@ -610,7 +613,7 @@ endif()
 if(ENABLE_LIBXC)
   find_package(Libxc CONFIG REQUIRED)
   if(Libxc_VERSION VERSION_LESS "5.1.7")
-    message(FATAL_ERROR "Libxc >= 5.1.7 is required")
+    message(FATAL_ERROR "Libxc >= 5.1.7 is required; found version ${Libxc_VERSION}")
   endif()
 endif()
 
diff --git a/source/source_hamilt/module_vdw/test/CMakeLists.txt b/source/source_hamilt/module_vdw/test/CMakeLists.txt
index 5f50e42ebfa..195a5312ce8 100644
--- a/source/source_hamilt/module_vdw/test/CMakeLists.txt
+++ b/source/source_hamilt/module_vdw/test/CMakeLists.txt
@@ -12,6 +12,12 @@ AddTest(
   SOURCES vdw_test.cpp vdwd3_evaluator_test.cpp
 )
 
-if(ENABLE_DFTD4)
-  target_link_libraries(MODULE_HAMILT_vdwTest PRIVATE dftd4::dftd4)
+if(ENABLE_DFTD4 AND ENABLE_MPI)
+  add_test(
+    NAME MODULE_HAMILT_vdwd4Test_2np
+    COMMAND ${MPIEXEC_EXECUTABLE} ${MPIEXEC_NUMPROC_FLAG} 2
+            ${MPIEXEC_PREFLAGS} $<TARGET_FILE:MODULE_HAMILT_vdwTest>
+            --gtest_filter=vdwd4Test.* ${MPIEXEC_POSTFLAGS}
+    WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
+  )
 endif()
diff --git a/source/source_hamilt/module_vdw/vdwd4.cpp b/source/source_hamilt/module_vdw/vdwd4.cpp
index 72caf51232a..ad4a93e9925 100644
--- a/source/source_hamilt/module_vdw/vdwd4.cpp
+++ b/source/source_hamilt/module_vdw/vdwd4.cpp
@@ -3,6 +3,10 @@
 
 #include "source_base/constants.h"
 #include "source_base/element_name.h"
+#ifdef __MPI
+#include "source_base/parallel_reduce.h"
+#include <mpi.h>
+#endif
 #include "source_base/timer.h"
 #include "source_base/tool_quit.h"
 
@@ -231,6 +235,15 @@ void Vdwd4::compute(double& energy_ha,
                                             smooth_width_3b_);
     check_dftd4_error(error, "dftd4_set_model_realspace_cutoff_smooth");
 
+#ifdef __MPI
+    int rank = 0;
+    int nranks = 1;
+    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+    MPI_Comm_size(MPI_COMM_WORLD, &nranks);
+    dftd4_set_model_work_partition(error, model, rank, nranks);
+    check_dftd4_error(error, "dftd4_set_model_work_partition");
+#endif
+
     std::vector<char> method(xc_name_.begin(), xc_name_.end());
     method.push_back('\0');
 
@@ -247,6 +260,18 @@ void Vdwd4::compute(double& energy_ha,
     dftd4_get_dispersion(error, mol, model, param, &energy_ha, gradient, sigma);
     check_dftd4_error(error, "dftd4_get_dispersion");
 
+#ifdef __MPI
+    Parallel_Reduce::reduce_all(energy_ha);
+    if (gradient != nullptr)
+    {
+        Parallel_Reduce::reduce_all(gradient, 3 * ucell_.nat);
+    }
+    if (sigma != nullptr)
+    {
+        Parallel_Reduce::reduce_all(sigma, 9);
+    }
+#endif
+
     dftd4_delete_param(&param);
     dftd4_delete_model(&model);
     dftd4_delete_structure(&mol);
diff --git a/toolchain/scripts/package_versions.sh b/toolchain/scripts/package_versions.sh
index 96b48f0c1db..0f19e9db4f3 100644
--- a/toolchain/scripts/package_versions.sh
+++ b/toolchain/scripts/package_versions.sh
@@ -85,8 +85,8 @@ scalapack_alt_sha256="a2f0c9180a210bf7ffe126c9cb81099cf337da1a7120ddb4cbe4894eb7
 # =============================================================================
 
 # DFT-D4 dispersion correction
-dftd4_ver="4.2.0"
-dftd4_sha256="467e024071510ad82b862c66c383c2ebc164fc1140e15dfc79f48d2f999fd184"
+dftd4_ver="4.3.0"
+dftd4_sha256="e94c5d021c0a4b4aa9b5587e36fda2f398271dc2dc1abfbe097fdb04022bef35"
 
 # LibTorch (supports dual versions) - main=2.1.2, alt=1.12.1
 libtorch_main_ver="2.1.2"